California utility San Diego Gas & Electric (SDG&E) on February 24 officially put into service what is currently the largest lithium-ion storage battery in the world, wrapping up a fast-track procurement process that began less than a year ago.

The 30-MW, 120-MWh system (Figure 1) supplied by AES Energy Storage and located in Escondido about half an hour north of San Diego is part of an expedited response by the state and the California Public Utilities Commission (CPUC) to the loss of the Aliso Canyon natural gas storage facility north of Los Angeles last year. The sudden loss of that storage capacity put major constraints on the area’s gas-fired generation and meant that peaker facilities faced the risk of not having gas to run when they were needed.

1. Bulk storage. San Diego Gas & Electric’s new 30-MW, 120-MWh battery storage system in Escondido, Calif., is the largest grid-connected battery in the world. Source: POWER/Tom Overton

Gov. Jerry Brown declared a state of emergency over the leak, and the CPUC in May told the state’s utilities to expedite plans for meeting their obligations under the agency’s energy storage mandate.…

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